With the popularization of the Internet, technologies have been under development to realize the control of electrical household appliances connected to a home network via the Internet (refer to Japanese Patent Laid-open No. 2002-44765, for example) and the sharing of the same content among a plurality of terminal devices (personal computers and so on) connected to the Internet, for example.
For the programs for remotely controlling electrical household appliances by using personal computers via a network, UPnP, Jini, and HAVi are known for example. These programs are middleware, and the user interface, which is operated by users for controlling their electrical household appliances, depends on other software programs using the middleware such as UPnP.
Methods of sharing content through the Internet include one in which content is communicated in file data based on FTP and HTTP and another in which content is communicated in stream data based on RTSP and RTP. These methods can restrict the destinations of content transfer by means of the authentication based on personal ID and password before content is transferred.
Technologies for authenticating electrical household appliances connected to a home network include 5C protection being applied to the authentication between the digital BS broadcast receiver and the digital video recorder, for example.
Incidentally, a method is disclosed in Japanese Patent Laid-open No. 2001-154966 for example in which a plurality of users simultaneously participate in a virtual space built on a computer network represented by the Internet, thereby realizing realtime communication.
The related-art software programs for realizing user interfaces for the remote control of electrical household appliances have only the functions of controlling electrical household appliances, namely, practicality, in many cases. Therefore, these related-art software programs present a problem that they cannot satisfy the needs of users who demand not only practicality but also amusement on the software programs of their personal computers.
The related-art technologies of forming communication in a virtual spaces also presents a problem of the lack of close communication between users because the forming of communication is achieved by users' entering public virtual spaces.
The virtual spaces realized by related-art technologies present a problem that the content provided by a participant of one of the virtual spaces cannot be shared realtime by other participants.
However, if the related-art methods in which content is shared via the Internet by means of FTP, HTTP, RTSP, and RTP are applied to the virtual spaces realized by related-art technologies, the content provided by a participant of one of the virtual spaces can be shared by other participants; but, in this case, if the personal ID and password for authentication are made public, a problem occurs in which copyrighted material may be distributed as content in an unauthorized manner.